1. Field of the Invention
The present invention relates to a multimedia network system and a method of multimedia communication with which provision of information and provision of services can be efficiently and systematically carried out.
2. Description of the Related Art
Multimedia network systems which integrate computer, broadcasting, publishing, and other media are now being researched and developed.
The multimedia network systems which have been proposed up to now have been comprised by a large number of terminals for consumers utilizing so-called multimedia computers etc, and information and service organizers for providing multimedia information such as audio and video data and text data or providing services such as banking or shopping connected via a digital communication network such as an integrated services digital network (ISDN) communication network, cable television (CATV) communication network, and asynchronous transfer mode (ATM) communication network with data being transmitted among these nodes.
In such a multimedia network system, a provider of a service stores content and provides the same to the network, while a consumer connects to the server of the provider to receive the provision of the information. This is the same for both the Internet and other networks such as CATV communication networks. Alternatively, the network provider has the function of providing of a service and realizes a similar service. The contents are expressly stored in the server and then provided to the network.
However, as the configuration of the multimedia network system becomes more complex and sophisticated, the number of the types of the nodes having different functions (network elements) is increased. For example, the present day multimedia network systems do not distinguish between an information provider providing multimedia information and a service organizer providing a service and treat them in the same way. However, in the provision of multimedia information, for example, audio and video information, the characterizing feature is that the amount of data transmitted from the provider side toward the consumer is enormous while the data transmitted from the consumer toward the provider is limited to the data for designating the information etc. so the amount of the data is very small. On the other hand, in the provision of a service, the characterizing feature is that the total amount of the transmitted data is small in comparison with the case of provision of multimedia information, but it is necessary to transmit the data in two directions between the service organizer and the consumer. Is the processing contents of nodes having respective characterizing features and performing different roles in this way are handled without distinguishing between them, the control of the communication among the nodes of the multimedia network system becomes complex and the systematic provision of multimedia information and services becomes difficult.
Further, for example, in the case of a video-on-demand (VOD) system for sending audio and video data (VOD data) in response to a request of a consumer, a VOD data generating apparatus for generating the VOD data and a VOD data transmitting apparatus for transmitting the generated VOD data to the viewers become necessary. In this way, the realization of complex and sophisticated data processing and communication processing sometimes requires that a plurality of nodes which are connected to each other via the multimedia network system be made to operate in a cooperative and coordinated manner (cooperate) to realize a single function. however, the multimedia network systems proposed at present do not function to support cooperative and coordinated operations of a plurality of nodes. For this reason, it is necessary to provide all of the constituent elements required by the data and service organizing systems including a plurality of nodes, and it is difficult for a plurality of data and service organizing systems to share hardware resources.
Further, it is conceivable that there will become required to connect a plurality of multimedia network systems with each other to constitute a further larger scale network system. In such a case, not all of the plurality of multimedia network systems will always be constituted using the same communication networks. For example, it may become necessary to connect a multimedia network system using for example a CATV communication network or ISDN network etc. and a multimedia network system using an ATM communication network with each other.